Museums are usually hit or miss. This one, however, is all acid hits.

The museum, named the Institute of Illegal Images, contains several million ‘tabs’ of acid. Collector Mark McCloud has amassed his colorful collection over the past 30 years, since the 1970s.

“When I first noticed the blotter prints, I said, ‘Boy, this is fascinating, and maybe I should try to collect some of these so our children know what happened to us,’” McCloud says.

Each sheet of acid contains different designs and artworks, making the psychedelic artifacts tiny little works of art. Most “blotter art” was created so that consumers could identify where the acid came from. Some acid designs went as far as to give subtle clues as to which chemist created them. For example, when Mr. Bill appeared on a blotter, it signified that the sheet came from a certain chemist named Mr. Bill, McCloud says.

While blotter art isn’t as prevalent as it once was, it’s still out there, and people are still making, buying, and using acid. “It’s still happening, like at those [Grateful] Dead shows going on recently,” McCloud says. “But it looks different now. I saw one that looked 3-D. Lenticular.”